Variable mechanical means for an oscillation circuit



Jan. 4, 1938. H. MUTH 2,104,569

VARIABLE MECHANICAL MEANS FOR AN OSCILLATION CIRCUIT Filed Nov. 21, 1934 INVENTOR HERBERT MUTH ATTO R N EY l3 BY 2,104,569 PATENT OFFICE I VARIABLE MECHANICAL MEANS FOR AN OSCILLATIONCIRCUIT Herbert Muth, Berlin,

, assignor to Tele- Germany funken Gesellschait fiir Drahtlose Tekllilihle m. b. H., BerlimGermany, a c p r ion of Germany Application November 21, 1934, Serial No. 754,187 In Germany November 9, 1933 3 Claim.

This invention relates to an improved hermetically closed oscillation circuit or oscillation circult element whose reactances (coils, capacities, or both) .are regulable from the outside by a 5 rotor spindle.

In many cases it is necessary to so build oscillation circuits so that they become independent of the fluctuations of atmospheric pressure and atmospheric humidity. The safest means to that end probably would consist in an oil seal. However, this inheres the drawback that the device cannot be mountedin any desired position, not to mention the fact that the oil is likely to occasion the introduction of impurities or dirt in the device.

Now, the invention is'based upon the proper appreciation of the fact that an adequately hermetic closure is insurable even by passing the control spindle through the .wall in the form of a worm or screw union.

Two exemplified embodiments of the construction of this invention are diagrammatically illustrated in the drawing, in which Fig. 1 is a sectional view of a variable condenser having an operating spindle connected to the control knob by a crank arrangement, and Fig. 2 is a sectional view of a variable condenser having the operating spindle rotating by threaded means in the wall of the container.

Referring to Fig. 1, there is shown a metallic vessel I, which may be provided with a cover IA soldered or welded at IB in any suitable I manner to form a hermetically sealed container for enclosing the apparatus to be adjusted, inside which container l is accommodated some suitable regulable or adjustable element comprised in the oscillation circuit, for instance, a rotor ll seated on the spindle 2 of a rotary condenser. This spindle is connected by way of a crank arrangement 3, 4, with the control or regulating spindle I brought into the container from the outside. The control knob 6 of the said spindle is fixedly connected with a bush 1 which interiorly is provided with a screw thread 8 and which therefore is capable of rotation upon a bush 0 secured on the container and having amatching male screw thread. The bush 8 is hermetically united withthe vessel l by means of a soldered Joint.

The rotor plates are insulated from the casing by member 3 being of insulating material, also by the insulated bearing bushing l2 and casing bushing ll. External connections are made by screws i4, nutli and lead It. The stator plates it are connected directly to the casing l, and external connections are made by screw l9 and nut 20. I In the exemplified embodiment shown in Fig. 2 it is the control shaft I which is furnished with a screw-thread i2. in this we. as in the member cooperating with the thread on said exprevious embodiment, casing l is formed in two parts and-welded together, the rotor plates are insulated by member 3A and bushings i2 and II, the twisting of the control spindle 5 occasions rotation of the rotor spindle 2. The female 5 screw thread in this instance is provided in the wall of vessel I. Tests have shown that such form of packing represents a sufllciently her-' metic seal and closure for all practical purposes.

I claim: 1 10 1. A variable condenser whose capacity is varied from the outside comprising a metallic oasing, fixed and movable electrode members within said casing, a. shaft secured to said movable electrode members, a shaft passing through an ex- 15 ternal bushing on said casing, a crank arrangement within said casing and coupled between said first and second mentioned shafts, an operating knob secured to said second shaft, said external bushing having a screw threadlocated thereon, said operating knob having a depending threaded member cooperating with the thread on said external bushing for rotating said'movable electrode members with respect to said fixed electrode members. 25

2. A hermetically sealed variable condenser whose capacity is varied from the outside com: prising a hermetically sealed casing, fixed and movable electrode members within said casing, a shaft secured to said movable electrode members, 30 a shaft passing through an external bushing on said casing, a crank arrangement within .said casing and coupled between said first and second mentioned'shafts, an operating knob secured to said second shaft, said external bushing having 35 a screw thread located thereon and beingin the same plane as said first and second shafts, said operating knob having a depending threaded temal bushing i'or rotating said movable electrode members with respect to said fixed electrodemembers.

3. A hermetically sealed variable condenser element whose capacity is varied from the out- 45 side comprising a hermetically sealed casing, fixed and movable electrode members within said casing, a shaft secured to said movable electrode members, a second shaft passing through said casing, a crankarranged within said casing 0 said fixed electrode members.

TWMUTH. 

